The model shows the structure of graphite, one of the allotropes of
carbon. Its structure is comprised of hexagonal layers of carbon atoms.
One such hexagonal layer, shown in yellow, is called a graphene sheet.

A graphene sheet can be rolled to form another allotrope of carbon
called a carbon nanotube. The graphene sheet can be rolled more than one
way, producing different types of carbon nanotubes.Download a pdf file with hexagonal
sheets. Print on paper to roll your own nanotube. Printing this file on
a plastic transparency will let you show this experiment on an overhead
projector.

The graphene sheet can be rolled more than one way, producing different
types of carbon nanotubes. The three main types are armchair, zig-zag,
and chiral.

Carbon nanotubes flash when placed in a microwave oven. An orange
solid remains, presumably iron oxide derived from the iron catalyst used
in producing the nanotubes. A control experiment using iron powder (<
10 micron diameter) showed no effect under the same conditions.

Diamond is another allotrope of carbon.
*Magnetic models created by Eatai Roth, Anne-Marie Nickel,
and Tim Herman through the Milwaukee School of Engineering NSF-sponsored REU
program using the Rapid Prototyping Center and the Center
for Biomolecular Modeling